Textile webs or fabrics in general are subject to curling along their edges or selvages while being handled in open width and often develop curls, pressed folds, pleats or creases therealong due to improper handling, improper web tension or the like. Knit or other flimsy textile fabrics, and particularly when they are processed or handled under tension, or in a generally tensionless condition, tend to curl or roll up along the selvage. In order to produce a good quality roll of textile fabric, or to achieve proper fabric handling along a process line for printing, inspection, drying, extraction of moisture, washing, doubling, tacking or other web treatment it is desirable, if not necessary, to ensure that the web is maintained in a flat condition where little or no fabric deformation is present at either of the selvages during the winding or processing as set forth above. When such webs or fabrics are fed to the usual tenter frame, it is necessary to decurl the edges of the fabric before engaging the selvages or the edges thereof with the pins on the tenter frame chain.
In one known tenter frame, the fabric is supplied from a roll of fabric over a feed roll which is on a level or horizontal plane, which is higher than the horizontal plane occupied by the tenter chain on which the fabric must be impinged and engaged. In this device, the selvages of the fabric are engaged by a temple which has a spiral row of teeth or pins and is adapted to spread the edge of the fabric before it enters the area of the tenter chain pin. In order to engage the edge of the fabric upon the pins of the tenter chain, it is necessary that the fabric be directed over the area of the tenter chain pins so that it can be pressed into the pins by a revolving brush or a roll having short bristles thereon which may be penetrated by the pins on the tenter chain. In such devices it is necessary for the edge of the fabric to follow a convoluted path which distorts or stretches the edges of the fabric and applies uneven tension thereon. Such tenters are sold under the trade name, Montex Stenter System by The Consultex Corporation of Spartanburg, S.C. and are manufactured by A. Monforts GmbH & Company Maschinenfabrik of MonchenGladbach in the Federal Republic of Germany.
Other tenters use a static decurling device such as that shown in U.S. Pat. No. 4,578,845, issued Apr. 1, 1986 to William O. Young, Jr. The Young web edge decurler of this patent has been commercially successful and performs the decurling operation in a very simple fashion. However, the decurler of Young is generally supported on the horizontal plane of the tenter rail before the fabric passes about a roller brush for being pressed into the pins of the conventional tenter frame. The transition from the plane in which the static web decurler lies to the lower generally horizontal plane wherein the tenter chains are disposed, is performed by guiding the fabric in contact about the surface of a large rotating brush or roll covered with bristles which guides the fabric from the level of the static web decurler to the lower level of the tenter chains, while at the same time pressing the edge of the web onto the pins of the tenter chain. However, it has been found that the use of the large diameter rollers for assisting in the transition of the fabric from the level of the static decurler to the lower level wherein the fabric is impinged upon the pins of the tenter frame results in considerable distortion or stretching of the edges of the fabric.
Further, in feeding flimsy fabrics to tenters under low tension, the center of the fabric tends to sag and causes an increased tendency for the edges of this fabric to curl. It is necessary that the edges of the fabric be controlled from the decurler until they are engaged by the tenter chains to avoid their recurling after passing through the decurler.